So far there have been used a great number of devices for the inspection and sorting of small objects, particularly fruits and small edible products, based on the transportation through endless means, such as bands, chains, or conveyor belts, of the fruits to be inspected, to a section in which their inspection is carried out. This inspection, as the case may be, can consist of different analysis, such as size, shape and existing defect analysis, or a sorting and separation of fruits based on size, shape, etc.
These devices for fruit inspection are for example the devices for the automatic sorting of agricultural products, such as fruits, with a roller conveyor, said rollers being tilted to distribute the products to different auxiliary paths and a measuring station.
Other devices are formed by a fruit and vegetable treatment and manipulation train, which also has a pre-selection conveyor which through the rollers derives the products to different stations. Another gauging conveyor rejects the units which are too big or too small.
These machines have the inconvenience that they do not carry out very detailed or precise selections, not detecting small shape variations or visually noticeable defects,
In the particular case of pistachios, the objective is to carry out an analysis of pistachios in order to eliminate those that are closed and represent an obstacle or a problem for consumption. At present, these analyses for identifying closed pistachios are carried out by mechanical methods or acoustic means, which, in addition to having a complex operation, also present a large number of errors; thus, these are not efficient in separating closed from opened pistachios.
Specifically, Document GB730434 shows a machine for sorting small fruits, such as peas and pistachios. The machine presents a rotating drum containing a plurality of to needles and a rotating brush on the inside. This technology presents the disadvantage that the drum needles damage the fruit during machine operation. In addition, said technology presents the additional problem that needles may break on occasions and small pieces may get stuck in the fruit, thereby entailing a food safety risk.
It was therefore desirable a system which attained an adequate pistachio inspection and sorting and an efficient separation of closed from opened pistachios, thus avoiding the inconveniences existing in the previous methods in the state of the art.